Antimalarial activity of cassane- and norcassane-type diterpenes from Caesalpinia crista and their structure-activity relationship.

Malaria is one of the most life-threatening infectious diseases worldwide and claims millions of people's lives each year. The appearance of drug-resistance Plasmodium falciparum has made the treatment of malaria increasingly problematic, and thus, it is a dire need to search the new alternatives of current drugs. In the present study, 44 cassane- and norcassane-type diterpenes isolated from Caesalpinia crista of Myanmar and Indonesia were evaluated for their antimalarial activity against the malaria parasite Plasmodium falciparum FCR-3/A2 clone in vitro.

Constituents of Caesalpinia crista from Indonesia.

Ten new furanocassane-type diterpenes named, caesalpinins H-P (1-9) and norcaesalpinin F (10), were isolated from the CH(2)Cl(2) extract of the seed kernels of Caesalpinia crista, together with 13 known diterpenes. Their structures were determined based on the spectroscopic analysis. Among the isolated compounds, caesalpinin N (7) represents the first example of furanocassane-type diterpene possessing an aldehyde group at C-14.

Methyl migrated cassane-type furanoditerpenes of Caesalpinia crista from Myanmar.

From the CH2Cl2 extract of seed kernels of Caesalpinia crista from Myanmar, two rare and biogenetically interesting methyl migrated cassane-type furanoditerpenes [caesalpinins MM (1) and MN (2)] and two normal cassane-type furanoditerpenes [caesalpinins MO (3) and MP (4)] have been isolated, together with eight known cassane-type diterpenes, 1-deacetoxy-1-oxocaesalmin C (5), 1-deacetylcaesalmin C (6), caesalmin C (7), bonducellpin C (8), caesaldekarin e (9), 2-acetoxycaesaldekarin e (10), 2-acetoxy-3-deacetoxycaesaldekarin e (11), and norcaesalpinin E (12). Among the known compounds, compounds 5 and 6 were for the first time isolated from a natural source. The structures of these compounds were elucidated by the use of spectroscopic techniques.

New cassane-type diterpenes of Caesalpinia crista from Myanmar.

Seven new cassane-type diterpenes, caesalpinin MF-ML (1-7), and a new norcassane-type diterpene, norcaesalpinin MD (8), have been isolated from the CH2Cl2 extract of seed kernels of Caesalpinia crista from Myanmar, together with sixteen known cassane-type diterpenes, 7-acetoxybonducellpin C, caesaldekarin e, caesalmin C, caesalmin G, 2-acetoxycaesaldekarin e, zeta-caesalpin, caesalpinin D, caesalpinin E, caesalpinin F, caesalpinin H, caesalpinin I, caesalpinin J, caesalpinin K, caesalpinin M, caesalpinin N, and caesalpinin O. The structures of the isolated compounds were elucidated by the use of spectroscopic techniques.

Antiproliferative activity of cardenolides isolated from Streptocaulon juventas.

Sixteen cardenolides, two hemiterpenoids, two phenylpropanoids and a phenylethanoid isolated from the roots of Streptocaulon juventas (LOUR.) MERR. were examined for their antiproliferative activity toward three human-derived (HT-1080 fibrosarcoma, lung A549 adenocarcinoma, cervix HeLa adenocarcinoma) and three murine-derived (colon 26-L5 carcinoma, Lewis lung carcinoma, B16-BL6 melanoma) cell lines.

Antiproliferative activity of Vietnamese medicinal plants.

Methanol, methanol-water (1:1) and water extracts were prepared from seventy-seven Vietnamese medicinal plants and tested for their antiproliferative activities against human HT-1080 fibrosarcoma cells. Among them, fifteen extracts including seven methanol extracts of Caesalpinia sappan, Catharanthus roseus, Coscinium fenestratum, Eurycoma longifolia, Hydnophytum formicarum and Streptocaulon juventas (collected at two areas), six methanol-water (1:1) extracts of Cae. sappan, Cat.